Vascular filter with improved strength and flexibility

Abstract

A medical device, such as a vascular filter, composed of: a reinforced membrane unit composed of: a thin filter membrane; and fibers of reinforcement material embedded in the membrane to strengthen the filter and securely attach the fibers to the membrane. A method of fabricating the filter by the steps of: providing a mold that can be melted, dissolved, or deformed without damaging membrane material; covering the mold with an intermediate material that is easily separated from the membrane material; covering the intermediate material with the membrane material; placing the fibers in contact with the membrane material that covers the intermediate material; covering the fibers with additional membrane material to form the membrane with embedded fibers; removing the mold by melting, dissolving, or deforming the mold; and removing the intermediate material from the membrane.

1. A system for preventing embolism and microembolism in a vascular system, said system comprising:
 a guiding catheter having an outer surface; 
 a blocking balloon carried by said guiding catheter on said outer surface 
 an elongated support element arranged to extend through, and beyond, said guiding catheter; 
 a first filter element with millipores carried by said support element and radially expandable from a closed condition to an open condition; 
 a second filter element surrounding said support element and radially expandable from a closed condition to an open condition; and 
 means coupled to at least one of said filter elements for moving said at least one of said filter elements between its respective closed and open conditions independently of movements of the other one of said filter elements between its respective closed and open conditions, 
 
     wherein:
 each of said filter elements has an open front end constituting a passage through which particles pass into said filter element, a bottom end remote from said front end and a filter surface structured to prevent passage of particles and permit passage of blood; 
 said first filter element has a conical shape with an apex at said bottom end, or a basket shape that is closed at said bottom end; 
 said elongated support element is secured to said bottom end of said first filter element; 
 said second filter element has a periphery delimiting said open front end and a central opening at said bottom end, spaced inwardly from said periphery; and 
 said elongated support element extends through said central opening in said second filter element. 
 
   
   
     2. A system for preventing embolism and microembolism in a vascular system, said system comprising:
 an elongated support element; 
 a first filter element with millipores carried by said support element and radially expandable from a closed condition to an open condition; 
 a second filter element surrounding said support element and radially expandable from a closed condition to an open condition; and 
 means coupled to at least one of said filter elements for moving said at least one of said filter elements between its respective closed and open conditions independently of movements of the other one of said filter elements between its respective closed and open conditions, 
 wherein
 each of said filter elements has a filter surface structured to prevent passage of particles and permit passage of blood; 
 at least one of said filter elements comprises: 
 
 an armature constituted by a mesh or screen made of a resiliently deformable material, said armature having surface; 
 and a sheet of polymer filter material secured to, and covering the surface of, said armature and providing said filter surface; 
 said first filter element has a conical shape with an apex or a basket shape with a closed bottom; 
 said elongated support element is secured to said apex or said bottom of said first filter element; 
 said second filter element has a periphery and a central opening spaced inwardly from said periphery; and 
 said elongated support element extends through said central opening in said second filter element. 
 
   
   
     3. A system for preventing embolism and microembolism in a vascular system, said system comprising:
 an elongated support element; 
 a first filter element with millipores carried by said support element and radially expandable from a closed condition to an open condition; 
 a second filter element surrounding said support element and radially expandable from a closed condition to an open condition; and 
 means coupled to at least one of said filter elements for moving said at least one of said filter elements between its respective closed and open conditions independently of movements of the other one of said filter elements between its respective closed and open conditions, 
 wherein:
 each of said filter elements has a filter surface structured to prevent passage of particles and permit passage of blood; and 
 one of said filter elements comprises:
 an armature made of a resiliently deformable material and having an open end; 
 a sheet of polymer filter material secured to said armature and providing said filter surface; 
 a flexible additional filter sheet having a periphery secured to the open end of said armature; and 
 a wire attached to said flexible additional filter sheet at a point spaced inwardly from said periphery and extending to a point outside of the vascular system, said wire being movable at the point outside of the vascular system to alter the shape of said flexible additional filter sheet. 
 
 
 
   
   
     4. The system according to  claim 3 , wherein said flexible additional filter sheet has filter holes dimensioned to prevent passage of particles that pass through said sheet of polymer filter material of said one of said, filter elements. 
   
   
     5. The system according to  claim 4 , wherein said one of said filter elements is said first filter element.